标题： 通过自旋回波谱学观察引力引起的极化超冷中子垂直条纹 显示英文标题

标题： Observation of gravitationally induced vertical striation of polarized ultracold neutrons by spin-echo spectroscopy

摘要： 我们描述了一种用于在进动室中被限制的超冷中子（UCN）并暴露于$|B_0|=1~\text{\mu T}$磁场的自旋回波方法。 我们已经证明，通过结合对UCN自旋回波共振信号的分析和对周围磁场的了解，可以提供一种极好的方法来重建受限中子集合的能量谱。 该方法利用了由于不同能量存储的UCN的重力诱导条纹而导致的自旋相对去相位，并且还允许以$1.1~\text{pT/cm}$的卓越精度确定垂直磁场梯度。 这种将一种众所周知的核共振方法与重力引起的垂直条纹相结合的新颖方法在核物理和粒子物理领域是独一无二的，应该在评估精密实验中的系统效应方面证明其无价，例如中子电偶极矩的搜索或中子寿命的测量。 显示英文摘要

摘要： We describe a spin-echo method for ultracold neutrons (UCNs) confined in a precession chamber and exposed to a $|B_0|=1~\text{\mu T}$ magnetic field. We have demonstrated that the analysis of UCN spin-echo resonance signals in combination with knowledge of the ambient magnetic field provides an excellent method by which to reconstruct the energy spectrum of a confined ensemble of neutrons. The method takes advantage of the relative dephasing of spins arising from a gravitationally induced striation of stored UCN of different energies, and also permits an improved determination of the vertical magnetic-field gradient with an exceptional accuracy of $1.1~\text{pT/cm}$. This novel combination of a well-known nuclear resonance method and gravitationally induced vertical striation is unique in the realm of nuclear and particle physics and should prove to be invaluable for the assessment of systematic effects in precision experiments such as searches for an electric dipole moment of the neutron or the measurement of the neutron lifetime.